Compilation fails on AIX with 7.55.1

[MikaelSmith]

I did this

I attempted to build curl 7.55.1 on AIX 7.1 using GCC 5.2.0.

I expected the following

I expected it to succeed, as we had previously built 7.51.0 successfully.

curl/libcurl version

7.55.1 (doesn't build, so no curl -V output)

operating system

AIX 7.1

Details

Compilation fails on multi.c. The root of it is that on AIX, when _ALL_SOURCE is set to 1 (as CURL does), sys/poll.h uses #define for event and revent. Because multi.c includes sys/poll.h but multi.h doesn't, we end up with a mismatch between names for the curl_waitfd struct.

libtool: compile:  gcc -DHAVE_CONFIG_H -I../include -I../lib -I../lib -DBUILDING_LIBCURL -isystem /opt/puppetlabs/puppet/include -isystem /opt/pl-build-tools/include -I/opt/puppetlabs/puppet/include -I/opt/puppetlabs/puppet/include/openssl -Werror-implicit-function-declaration -O2 -Wno-system-headers -pthread -MT libcurl_la-multi.lo -MD -MP -MF .deps/libcurl_la-multi.Tpo -c multi.c  -fPIC -DPIC -o .libs/libcurl_la-multi.o
multi.c: In function 'curl_multi_wait':
multi.c:1076:20: error: 'struct curl_waitfd' has no member named 'reqevents'
     if(extra_fds[i].events & CURL_WAIT_POLLIN)
                    ^
multi.c:1078:20: error: 'struct curl_waitfd' has no member named 'reqevents'
     if(extra_fds[i].events & CURL_WAIT_POLLPRI)
                    ^
multi.c:1080:20: error: 'struct curl_waitfd' has no member named 'reqevents'
     if(extra_fds[i].events & CURL_WAIT_POLLOUT)
                    ^
multi.c:1108:21: error: 'struct curl_waitfd' has no member named 'rtnevents'
         extra_fds[i].revents = mask;
                     ^
gmake: *** [libcurl_la-multi.lo] Error 1

Previously this appears to have built with curl 7.51.0 because multi.h also included sys/poll.h, so they were equally wrong. Based on https://curl.haxx.se/mail/lib-2013-02/0330.html, this appears to have been an issue off-and-on for years.

My workaround has been to undef _ALL_SOURCE before including select.h in multi.c, and redefine it after. This probably isn't a good general solution.

[bagder]

Undefining _ALL_SOURCE seems a bit rough (that define is added by configure/autoconf btw).

How about making sure sys/poll.h is included before multi.h is included like this patch? (curl_setup.h is the first file multi.c includes)

diff --git a/lib/curl_setup.h b/lib/curl_setup.h
index 36d1e42bc..6ed230ac2 100644
--- a/lib/curl_setup.h
+++ b/lib/curl_setup.h
@@ -326,10 +326,14 @@
 
 #ifndef STDC_HEADERS /* no standard C headers! */
 #include <curl/stdcheaders.h>
 #endif
 
+#ifdef _AIX
+#include <sys/poll.h>
+#endif
+
 #ifdef __POCC__
 #  include <sys/types.h>
 #  include <unistd.h>
 #  define sys_nerr EILSEQ
 #endif

[MikaelSmith]

That would mess up anyone trying to use curl_waitfd outside multi.h. Probably not a problem in my code, but didn't seem like a great solution.

[bagder]

That would mess up anyone trying to use curl_waitfd outside multi.h

Exactly how would that mess anything up for anyone?

I would agree that it doesn't really help applications that want to use curl_waitfd, as they would have to include <sys/poll.h> on their own before multi.h to really fix this.

A better fix that also works for other applications could be to make sure <curl/system.h> includes it. What do you think?

diff --git a/include/curl/system.h b/include/curl/system.h
index a6640ba52..39dae754c 100644
--- a/include/curl/system.h
+++ b/include/curl/system.h
@@ -375,10 +375,16 @@
 # define CURL_SUFFIX_CURL_OFF_T     L
 # define CURL_SUFFIX_CURL_OFF_TU    UL
 # define CURL_TYPEOF_CURL_SOCKLEN_T int
 #endif
 
+#ifdef _AIX
+/* AIX needs <sys/poll.h> */
+#define CURL_PULL_SYS_POLL_H
+#endif
+
+
 /* CURL_PULL_WS2TCPIP_H is defined above when inclusion of header file  */
 /* ws2tcpip.h is required here to properly make type definitions below. */
 #ifdef CURL_PULL_WS2TCPIP_H
 #  include <winsock2.h>
 #  include <windows.h>
@@ -395,10 +401,16 @@
 /* sys/socket.h is required here to properly make type definitions below. */
 #ifdef CURL_PULL_SYS_SOCKET_H
 #  include <sys/socket.h>
 #endif
 
+/* CURL_PULL_SYS_POLL_H is defined above when inclusion of header file    */
+/* sys/poll.h is required here to properly make type definitions below.   */
+#ifdef CURL_PULL_SYS_POLL_H
+#  include <sys/poll.h>
+#endif
+
 /* Data type definition of curl_socklen_t. */
 #ifdef CURL_TYPEOF_CURL_SOCKLEN_T
   typedef CURL_TYPEOF_CURL_SOCKLEN_T curl_socklen_t;
 #endif
 

[MikaelSmith]

Yes, having to include <sys/poll.h> before using <multi.h> is what I meant by "mess up". It would likely be unintuitive.

I guess including it for anyone using curl is the a reasonable solution.

[bagder]

Thanks!